1. Technical Field
The present disclosure relates to an apparatus and method for treating blood vessels. More particularly, the present disclosure relates to an apparatus including a microwave antenna having a radiating loop configuration that is utilized for treating blood vessels.
2. Background of Related Art
In recent years a number of non-invasive techniques have been developed to repair abnormalities (e.g., aneurysms, arterio-venous fistulas, varicose veins, etc.) occurring in hollow body biological organs and/or vessels. Typically, the non-invasive techniques generally seek to “re-line” the blood flow path through the organ and/or vessel.
For example, in the instance of a vessel afflicted with an aneurysm, endovascular techniques typically involve attempting to form a mass within a sac of the aneurysm. Typically, a microcatheter (or other suitable device) is used to access the aneurysm. More particularly, a distal tip of the microcatheter is placed within a blood vessel (e.g., a parent artery or vein) that is in fluid communication with the sac of the aneurysm. Thereafter, the distal tip of the microcatheter is used to inject embolic material into the sac of the aneurysm. In certain instances, the embolic material may include, for example, detachable coils or an embolic agent.
Disadvantages associated with injecting embolic material into the sac of the aneurysm include migration of the embolic material out of the sac of the aneurysm and into the parent artery afflicted with the aneurysm. Migration of the embolic material can cause permanent and irreversible occlusion of the parent artery. For example, when detachable coils are used to treat, e.g., occlude, an aneurysm, the detachable coils may migrate out of the sac of the aneurysm and into the patient's artery. Moreover, it is, at times, difficult to gauge the exact size of the sac of the aneurysm when the detachable coils are being injected into the sac. Therefore, there is a risk of overfilling the sac of the aneurysm in which case the detachable coils may spill out of the sac of the aneurysm and into the patient's artery, which may result in permanent and irreversible occlusion of the patient's artery. Another disadvantage associated with the use of detachable coils in treating an aneurysm involves coil compaction over time. More particularly, after filling a sac of the aneurysm with detachable coils, space may remain between the detachable coils. Continued hemodynamic forces from blood circulation act to compact the detachable coil mass, which, in turn, may result in a cavity in the aneurysm neck. As a result thereof; the aneurysm may recanalize which, in turn, may lead to blood flowing through the neck of the aneurysm and into the sac of the aneurysm. Embolic agent (e.g., a liquid polymer) migration is also a problem. More particularly, when a liquid polymer is injected into the sac of the aneurysm, it (the liquid polymer) can migrate out of the sac of the aneurysm due to the hemodynamics of the system; this can also lead to irreversible occlusion of the parent vessel.
Another endovascular technique for treating aneurysms involves inserting a detachable balloon (or other suitable device) into a sac of the aneurysm using a microcatheter. In this instance, the detachable balloon is inflated using embolic material, such as liquid polymer material. The balloon is then detached from the microcatheter and left within the sac of the aneurysm in an attempt to fill the sac of the aneurysm and form a thrombotic mass in the aneurysm. However, detachable balloons also suffer disadvantages. For example, detachable balloons, when inflated, typically do not conform to the interior configuration of the aneurysm sac. Instead, the detachable balloon requires the sac of the aneurysm to conform to the exterior surface of the detachable balloon. Thus, there is an increased risk that the detachable balloon will rupture the sac of the aneurysm.
As an alternative to the foregoing endovascular techniques, or in combination therewith, a distal tip of a microwave antenna may be placed within a blood vessel (e.g., an artery or vein) that is in fluid communication with the sac of the aneurysm. In this instance, the microwave antenna and/or distal tip is configured to treat the aneurysm via electrosurgical energy (e.g., RF or microwave energy). More particularly, the distal tip is configured to heat the interior of the sac aneurysm, i.e., heat the blood within the aneurysm, until a thrombus or thrombotic mass is formed.